Chemistry
posted by Zach .
ΔT = T(mix)  T(initial)
And the equations is:
HCl(aq)+ NaOH(aq) => NaCl(aq) + H2O(l)
And T(mix) = 37 C
50.0 mL of 2.0M HCl = 23.7 C
50.0 mL of 2.0M NaOH = 23.5 C
How do I find T(initial), do I just use their averages? Thanks

As they are the same volume it is fine to average the two temperatures.
Especially as the subtraction
(3723.6)C = 13.4C which is 13C to zero dp. (The 37C with zero dp governs the number of dps in the answer).